Hexachlorocyclohexane: persistence, toxicity and decontamination.

Hexachlorocyclohexane (HCH), a persistent organochlorine insecticide, has been extensively used in the past for control of agricultural pests and vector borne diseases. The use of HCH has indeed accrued benefits, however the unusual production of the insecticidal isomer; γ-HCH (lindane) and unregulated disposal of HCH muck has created various dumpsites all over the world, leading to serious environmental concerns. HCH isomers have been ranked as possible human carcinogens and endocrine disruptors with proven teratogenic, mutagenic and genotoxic effects, hence making its decontamination mandatory. Efforts in this direction have led to the isolation of various HCH degrading bacteria from the dumpsites, reflecting their role in HCH bioremediation. This review summarizes the problem of environmental persistence of HCH isomers along with their toxicity and possible solutions for their decontamination.